1. Field of the Invention
The present invention relates to a collecting and withdrawing device for withdrawing exhaled gases from the area around the mouth and the nose of a patient. More particularly, the invention relates to a gas collection device adapted to be carried on the chin of a patient and having an opening adjacent the patient's mouth to receive gases exhaled by the patient.
2. Description of the Prior Art
In commonly owned U.S. patent application Ser. No. 739,812, filed May 31, 1985, there is disclosed an anesthetic mask that includes a double wall to define a passageway by which anesthetic gas that leaks from around the mask can be collected to prevent it from spreading in an operating room and adversely affecting the operating room personnel. However, such an anesthetic mask that covers the mouth of the patient is not usable for the continuous administration of anesthesia in, for instance, dental surgery, or in other operations performed in the oral cavity. Furthermore, during such oral operations, the surgeon is often exposed to considerable amounts of anesthetic gas that is exhaled by the patient.
Additionally, in the administration of analgesia for the relief of pain, for instance in connection with childbirth, the above-mentioned double wall anesthetic mask has proved less useful, primarily because the device for supplying the analgesic gas, i.e., nitrous oxide or laughing-gas, is of a design different from that of masks for supplying anesthetic gas. In the supply of analgesic gas, the patient often himself adjusts the supply of the gas by holding the mask before the nose and the mouth for relatively short periods and breathing freely to inhale the gas, and then removing the mask until additional gas is needed. The air exhaled by the patient is heavily charged with the analgesic gas, and unless withdrawn its concentration in the air around the patient increases rapidly. Thus it is desirable to provide a gas collection means to prevent such contamination of the air.
Another occasion on which it is advantageous to use a gas collection means is in the post-operative recovery room of a hospital, i.e., where the patients wake up after an operation and where they remain temporarily while the effect of the anesthesia is dissipating. The air exhaled by such patients also contains substantial amounts of anesthetic gas, and such rooms can therefore have a significant concentration of such gas.
An object of this invention is to provide a gas collection device which makes it possible readily to collect and withdraw primarily anesthetic or analgesic gas borne by the exhaled breath of a patient.